1. Field of the Invention
The present invention relates to a method for transmitting data, and an apparatus for transmitting data and a medium which can be used when for example, data representing video images, data representing sound and auxiliary data except them are inputted and outputted between an information recording and reproducing device and a computer.
2. Description of the Related Art
A device (VTR, video cameras, hard disks, optical disks or the like) for recording or reproducing information such as video images and sound has been connected to a computer through an exclusive interface or a network and data has been transmitted. Thus, an editing operation for the video images, sound or the like has been carried out on the computer. This technique for the recording and reproducing device is proposed by Japanese Patent Application No. 8-176934.
However, depending on the system configuration of a hardware or a software such as an operating system in a computer, the amount of data capable of being transmitted within a unit time which is assigned to each of various processings of an entire data transfer rate respectively changes. Therefore, there has occurred a problem that if the system configuration changes, a phenomenon in which it is impossible to transmit data or a reproduced video image is dropped out of a frame or the like occurs, or the data of an amount smaller than that which can be actually transmitted can be only transmitted with an efficiency lowered. Further, there has also arisen a problem that each time the system configuration changes, it is necessary to change a hardware or software.
In addition, there has occurred a defect that if the data is simultaneously edited while the data is transmitted, the data to be transmitted can not be fetched by mistake.
Still further, there has been proposed a method that when an excess transfer amount of the bus of a computer is compared with a requested transfer amount and the requested transfer amount exceeds the excess transfer amount, the request is stood by, and then, when the excess transfer amount recovers, the data is transferred.
However, according to this method, even when the excess transfer amount of the bus remains or is left, if the requested transfer amount exceeds the former, the request must be waited for. Therefore, the excess part of the bus is undesirably wasted.